Adipose tissue is recognized as a promising source of stem cells with at least multi-potent differentiation potential. Lipoasperate obtained during a lipoplasty procedure, such as lipo surgery, may be processed to prepare a so-called stromal vascular fraction (SVF) that is rich in leuko stromal vascular cells, which include stem cells. Processing to prepare SVF may include washing lipoasperate with saline solution, followed by enzymatic digestion of washed tissue using collagenase, and centrifuging digested material to prepare SVF in the form of a centrifuged pellet. Such collection and processing of tissue involves several steps with transfer of contents between different process containers for different tissue collection and processing steps, which is cumbersome and provides significant opportunities for error or contamination.
Some attempts have been made to design portable containers in which lipoasperate may be collected and then processed within the container to digest tissue and prepare a concentrate enriched in leuko stromal vascular cells. Potential benefits of using such portable containers include a reduced need to transfer material between containers to perform different process steps and a reduction in the need for multiple, specially-designed processing containers. However, such multi-step processing in portable containers faces significant equipment and process design and operating limitations, especially when attempting to process relatively large volumes of adipose tissue at one time. Desired leuko vascular cells, including stem cells, are sensitive to processing conditions and viability of recovered cells may suffer significantly if processing is not adequately controlled. Also, recovery of cells from the container is of critical importance. Significant potential exists for loss of valuable cells to recovery from the container, such as by cells adhering to internal equipment and surfaces within the container. One problem with multi-step processing in a single portable container is that the container design and processing operations must accommodate the different requirements of each of the different process steps to be performed in the single container, and with severe volume constraints in relation to a practical size for such a portable container. In contrast, processing systems that involve transfer of contents between multiple different containers for performance of different process steps benefit from an ability to optimize equipment and process design for each process container that is dedicated to performance of a single step of an overall process. Therefore, multi-container processing has significant advantages in terms of step-by-step equipment and process optimization. Moreover, a multi-container design is better suited for automation, for example with automated transfer of processed material through conduits between different process containers or with automated control of process parameters for uniformity and process control. Multi-container processing remains the predominant processing technique at this time for processing adipose tissue to prepare stromal vascular fraction concentrates.